1. Field of the Invention
The present invention relates to an internet facsimile communication system provided with (1) an internet facsimile adaptor apparatus which is connectable with a PSTN network and an IP network and is provided also with an analog port, and (2) a facsimile apparatus connected to the above-mentioned analog port.
2. Related Background Art
Recently, the ITU-T issued the Recommendation H.323 as a standard for communication of voice and image through the IP network. Also the ITU-T issued the Recommendation T.38 for real-time facsimile communication utilizing the IP network.
In response thereto, there is commercialized an adaptor based on such recommendations H.323 and T.38.
Such adaptor based on the Recommendations H.323 and T.38 is provided with a port for connection to the IP network and a port for connection to a telephone or a facsimile apparatus. By the adaptor, in case of an incoming call from the IP network, a voice call is subjected to voice encoding/decoding according to the encoding method defined in the Recommendation H.323 so as to ring a telephone set, and in case of a facsimile communication, the communication executed according to the Recommendation T.38 is converted into a system of the Recommendation T.30 so as to call for the facsimile apparatus.
An adaptor of this kind is usually provided with a port for connection to the IP network and also with a port for connection to the PSTN network.
Thus, a channel to be used is switched according to the necessity, since the connection with the IP network alone cannot establish communication with the telephone or the facsimile apparatus connected to the PSTN network.
The facsimile apparatus is to be basically connected to the PSTN network, and, at the reception of a call in such connection, it is not possible to judge whether the content of the communication is a voice communication or a fax communication. On the other hand, since there is a requirement of using one telephone line both for the telephone set and the facsimile apparatus, the facsimile apparatus is mostly provided with plural operation modes such as “TEL mode”, “FAX mode”, “FAX/TEL switching mode”, etc. and is used by switching such modes according to the necessity.
In the above-mentioned “TEL mode”, a FAX incoming call is not automatically responded but an incoming call is always responded by the telephone, and the facsimile apparatus is thereafter manually activated if necessary. In the “FAX mode”, a FAX incoming call is automatically responded by the facsimile apparatus to initiate a facsimile communication. In the “FAX/TEL switching mode”, the facsimile apparatus receives an incoming call and judges whether the counterpart is a person or a facsimile apparatus, and, in case of the person, calls the telephone set, but, in case of the facsimile apparatus, initiates the facsimile communication.
On the other hand, in case of the internet facsimile, the adaptor side can know in advance whether the content of communication is a voice communication by VoIP or a facsimile communication according to T.38.
However, since the adaptor and the facsimile apparatus are usually connected with a two-wire telephone line without any other interface, it is not possible to transmit additional information on the content of connection, so that, depending on the setting of the facsimile apparatus, there may be encountered a drawback that the incoming call is responded by the facsimile apparatus even when the adaptor side knows it is a voice communication, or inversely by the telephone even when the adaptor side knows it is a facsimile communication.
It is easily possible to avoid such drawback by connecting an exclusive I/F between the adaptor and the facsimile apparatus thereby transmitting additional information, but the preparation of such particular facsimile apparatus leads to an increased cost and precludes free combination of the adaptor and the facsimile apparatus, thereby restricting the range of selection.